I know ford says you can 10,000 miles between oil changes, but I still change My oil 3,500 to 4,000 miles. I keep my trucks on average 10-12 years, and tow alot. and my fords have always been in good runing condition when I trade them in, so I think changeing the oil more often is the way to go if you want your truck to last long term. I also use full synthetic oil and a Ford oil filter.
2011 F150 XLT Race Red Supercrew cab 4X4 Twin Turbo Ecoboost motor, 3:31 gears, Westin 9500lb T-MAX Wintch, Thule Adjustable Racks and Supper Bumper rear bumper guard.